FIG. 10.

C-signal dependence of developmental lacZ expression from the Ω4406 promoter. The average β-galactosidase specific activity of three independently isolated transformants (Materials and Methods) with the 1.0-kb (solid lines) or 1.8-kb (dashed lines) Ω4406 upstream DNA segment fused to lacZ in pPV12K and integrated at Mx8 attB of wild-type DK1622 (•) or csgA mutant LS203 in the absence (▵) or presence (▴) of an equal number of wild-type DK1622 cells (lacking lacZ but capable of C-signaling). β-galactosidase specific activity is expressed in nanomoles of o-nitrophenyl phosphate per minute per milligram of protein, and error bars show 1 standard deviation of the data.